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Table 1 Age and age-adjusted baseline characteristics of cancer-free women and breast cancer survivors in the BOSS cohort study

From: Evaluation of osteopenia and osteoporosis in younger breast cancer survivors compared with cancer-free women: a prospective cohort study

Characteristic Cancer-free Survivorsa p Value
(n = 567) (n = 211)
Ageb, years, mean (SD) 44.7 (11.3) 48.1 (10.3) < 0.001
Race, white, % 88.7 83.3 0.02
Education, ≥ 4 years of college, % 77.6 77.4 0.72
Postmenopausal, % 27.4 51.6 < 0.001
Age at menopausec, years, mean (SD) 49.6 (4.9) 48.8 (3.4) 0.86
Bilateral oophorectomy at age < 45 yearsd, % 49.0 34.3 0.02
BMI, kg/m2, mean (SD) 26.2 (5.1) 25.9 (3.1) 0.29
Physical activity, MET-h/wke, mean (SD) 29.4 (27.9) 26.0 (15.5) 0.29
Alcohol intake, g/d, mean (SD) 5.7 (7.5) 5.7 (4.8) 0.99
Smoking status, %
 Never 58.8 52.5 0.55
 Former 36.7 44.8
 Current 4.2 2.7
 Missing 0.3 0.0  
HRT ever use, % 15.1 14.5 0.04
Ever mammogramf, % 99.5 97.8 0.63
Ever pap smear, % 98.6 99.1 0.15
Current vitamin D supplement use, % 7.8 20.8 < 0.001
Current calcium supplement use, % 25.5 28.1 0.97
Bone density examination, % 28.9 43.0 0.02
Bone density examination in women aged ≥ 45 years, % 51.2 60.0 0.08
Ever broken bone, % 6.4 6.8 0.84
Family history of breast cancer, %
 No family history 14.7 38.9 < 0.001
 First-degree relative only 64.8 50.7
 First- and second-degree relatives 17.0 9.0
 Missing 3.5 1.4
BRCA1/2 statusg, %
 Negative 69.7 73.9 0.33
 Positive 27.3 19.4
 Variants of uncertain significance 2.9 6.7
Age at diagnosis, years, mean (SD) – 46.8 (10.2) –
Time from diagnosis to baseline, years, mean (SD) – 1.4 (1.3) –
Invasive breast cancer (stage I–III), % – 82.5 –
Estrogen receptor statush, % –   –
 Positive – 75.9 –
 Negative – 23.6 –
 Missing/untested – < 1.0 –
HER2 statush, % –   –
 Positive – 14.4 –
 Negative – 81.6 –
 Missing/untested – 3.5 –
Triple-negative statush, % – 19.0 –
Breast cancer treatmenti,j, % –   –
 Surgery – 100.0 –
 Chemotherapy – 49.8 –
 Hormone therapy, any – 65.4 –
 Hormone therapy, by typek –   –
  Tamoxifen – 67.4 –
  Aromatase inhibitor – 41.3 –
  1. Abbreviations: BMI Body mass index, HER2 Human epidermal growth factor receptor 2, HRT Hormone replacement therapy
  2. Values are means (SD) or percentages and are standardized to the age distribution of the study population
  3. aWomen were diagnosed with stages 0–III breast cancer ≤ 5 years prior to baseline
  4. bValue is not age-adjusted
  5. cAmong postmenopausal women
  6. dAmong women who had both ovaries removed (n = 86)
  7. eMetabolic equivalents from recreational and occupational activity
  8. fAmong women aged ≥ 50 years
  9. gAmong women tested for BRCA status (n = 414)
  10. hAmong invasive cases only (n = 174)
  11. iTreatment groups are not mutually exclusive
  12. jChemotherapy and hormone therapy are adjuvant
  13. kSeven percent of breast cancer survivors received both tamoxifen and aromatase inhibitors (n = 15)
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Breast Cancer Research

ISSN: 1465-542X

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